1. Field of the Invention
The present invention relates to a structure for a guide rail used in an automatic seat belt apparatus installed in a vehicle, which supports the guide rail on the vehicle body.
2. Related Art
A known guide rail supporting structure of the above-mentioned type is illustrated in FIG. 10. In the known supporting structure, the guide rail 10 has flanges or constrictions 12 formed in the widthwise sides (i.e., on the left and right sides as viewed in FIG. 10) of the guide rail 10. A holder 14 is engaged with the flanges 12 whereby the guide rail 10 is supported on a side wall 15 of the compartment via the holder 14. The holder 14 has a mounting plate portion 14A at which the holder 14 is mounted on the compartment side wall 15, a U-shaped portion 14B formed below the mounting portion 14A and adapted to receive the guide rail 10, and pawls 14C which are formed at the tips of the U-shaped portion 14B and extend in such a manner that the guide rail 10 is held between the pawls 14C on the widthwise sides thereof. The pawls 14C engage with the constrictions 12 of the guide rail 10 so as to support the guide rail 10. The holder 14 may be a type in which it is formed by bending a single plate material, as shown in FIG. 11, or it may be a type in which it is formed by two plate materials, as shown in FIG. 12.
With the known guide rail supporting structure, however, the constrictions 12 are formed in the vicinity of the end (i.e., the lower end as shown in FIG. 10) of the guide rail 10 that is closer to a portion where an associated webbing (not shown) is in engagement with a slider 16. As a result, when, for instance, the webbing is pulled inwardly of the compartment (i.e., toward the left side as viewed in FIG. 10) and the guide rail 10 is accordingly subjected to a lateral force acting in the direction A indicated by the arrow in FIG. 10, the constrictions 12 of the guide rail 10 move a distance which is too great for them to remain in engagement with the pawls 14C, and there is a tendency for one of the pawls 14C to be disengaged at such a time as shown in FIG. 13. In order to control the distance the constrictions 12 may move, it has been necessary to increase the strength of the holder 14.